1. Technical Field
The present disclosure is related to a manufacturing method of anti-fog coatings on lenses, and in particular, to a manufacturing method of anti-fog coatings on lenses made of plastic materials for swimming and/or sport goggles.
2. Description of Related Art
Situations where temperature changes rapidly can cause optical lenses to suddenly “fog up” and block vision. Since swimming or sport goggles are often exposed to the foregoing situation, anti-fog treatments are usually performed therefor.
Conventional anti-fog treatments for optical grade lenses involve spraying a thermal curing material on lenses, then heating and drying the thermal curing material on the lenses to form an anti-fog coating. Current manufacturing processes of anti-fog coatings for lenses usually includes the following steps: firstly, hanging the lenses on a rail hanger or a conveyor belt after cleaning surfaces of the lenses; then, removing dust from the surfaces of the lenses; afterwards, conveying lenses to an isolation chamber and spraying anti-fog materials on the lenses from nozzles; removing the extra anti-fog materials shedding from the surfaces of the lenses by suction nozzles; after that, preliminarily drying the anti-fog materials on the surfaces of lenses, and then, moving the lenses to an oven or a furnace for thermal curing, which cures the anti-fog materials on the lenses.
In conventional manufacturing processes of anti-fog coatings for lenses, the way the lenses are hung may cause shaking of the lenses and failure to precisely position the lenses during the spraying process even through automatic robotic arms. In order to make lenses steady, the lenses need to be positioned by human hands during the spraying treatment, which increases manual labor and affects the quality of products due to the uneven coating.
In addition, during the curing process, the sprayed and dried lenses are set on a conveyor belt by hands and conveyed through a tunnel furnace by the conveyor belt to conduct the curing steps for the anti-fog coating. However, since the curing process for the thermal curing material often takes a long time (usually up to 30 minutes), a thermal furnace with a long enough length is required, and lenses are required to be conveyed at a slow speed on the conveyor belt so as to prolong the heating time for the lenses in the furnace for full completion of the curing process of the anti-fog coating. Therefore, the conventional apparatus used for manufacturing the anti-fog coating on lenses not only occupies large space in a factory, but also has a low productivity.
In addition, since the length of the tunnel furnace used by the conventional manufacturing method is too long, working stations for each process of the manufacturing method must be arranged serially and in a long line, which not only occupies large spaces in the factory, but also requires a great amount of human resource due to the long distance between each working station, thereby increasing the manufacturing costs.
Therefore, there is a need in the art for a manufacturing method that overcomes the above disadvantages.